Health

Explainer: How Bad Is the 'Polio Vaccine Contamination' Controversy?

The alarm is warranted – the virus was found in the stool samples of two children out of hundreds to whom the vaccine was administered. Will India still be considered 'polio free'?

New Delhi: News broke this week that vials of oral polio vaccine were found to be “contaminated” with the polio virus. The virus was first found in the stool samples of two children out of hundreds to whom the vaccine was administered.

The alarm is warranted – India was declared “polio free” in 2014 by the World Health Organization, after being free of the wild polio virus for three years before that. This is a global accolade India wants to maintain. India’s success story with defeating polio is celebrated world over and is an important chapter in public health history.

The recent discovery of contamination in vaccines could change that. But the extent of the alarm could do with some perspective.

How many kinds of polio vaccines are there?

Polio vaccines are administered orally and through injectables. They can be bivalent or trivalent, depending on which strains of wild polio virus they protect against. Vaccines are given for Type 1, Type 2 and Type 3 polio virus.

Is there a chance people get polio from vaccines?

Yes. This is called “vaccine derived polio.” Vaccine derived illness and adverse effects are a risk run with all vaccines and even with drugs, but governments introduce vaccines and drugs in public programmes despite these risks, after doing a substantial cost versus benefit analysis.

Don’t vaccines already have strains of virus in it?

Yes. Finding strains of a virus in a vaccine is not automatically a contamination, adulteration or a public health hazard as such- this is how vaccines are designed to work. Vaccines work by introducing dead or less virulent strains of a vaccine into the body through the vaccine, which then kick starts the body’s own production of antibodies to fight off the real virus if it ever hits the body.

So what is the problem with polio virus being found in the polio vaccines recently?

Here’s the catch. Type 2 of the polio virus was declared eradicated globally, in September 2015. After this the World Health Organization recommended that polio vaccines can stop having the Type 2 strain and have this vaccine phased out. This reduces the risk of people catching vaccine derived polio as well.

India, along with other countries, adhered to this made the switch from the trivalent vaccine to the bivalent vaccine (which didn’t have the Type 2 strain) in April 2016. All manufacturers were told to destroy their stocks of vaccines with Type 2 of the polio virus in it.

The fact that this recent contamination in vaccines has been found in the products of Uttar Pradesh based company, Bio-Med, indicates that the strains of Type 2 virus were not effectively destroyed, that the strains were being kept as samples by some players and that the government’s monitoring of the destruction in 2016, was not thorough.

A government official told The Wire, “We have with us certificates submitted by Bio-Med saying that they destroyed all the stock of this vaccine and also that they recalled their stock from the market.”

How risky is this new situation?

For now, it is best to treat this situation with urgency as its risk can go either way.

Government officials say that the recent contamination may not be very risky. Firstly, two government officials have told The Wire that although the vaccines administered were bivalent (for only the Type 1 and Type 3 of polio virus), and although strains of Type 2 virus were found in these bivalent vaccines, Type 2 of the virus was not found in strong quantities. Secondly, the type 2 strain which was put into these contaminated vaccine was in an attenuated form, meaning it was of a less virulent form. An attenuated vaccine is “like a tiger without teeth,” said one government official. For both of these reasons, government officials say that the contamination may not necessarily be able to infect children with the polio virus itself.

However, since 2016, children in India have not been vaccinated against type 2 polio virus. “All babies born after April 24, 2016, when the Type 2 virus was withdrawn, are without immunity to type-2 virus. They would be susceptible to infections caused by the Type 2 virus that may regain neuro-virulence and spread,” said T. Jacob John, emeritus professor at the Christian Medical College, Vellore, to The Telegraph. The fact that the virus has been shedding into the sewage means it can enter the guts of children who are not immunised against it, and it can mutate into more virulent forms and spread.

So are the children clearly out of risk of getting polio?

Not necessarily. For now, strains of Type 2 were detected in the stool samples of these children. It is standard for children to “shed” the virus through their stool, for about three months after being given the polio vaccine. But to confirm on their polio status, takes about six months after being given the vaccine.

We will not allow polio myelitis to make a comeback,” said J.P. Nadda, Union health minister.

But this controversy is not at all, yet, in the clear.

Despite assurances given by the government, India’s surveillance programme for polio – which is carried out by the WHO with the Indian government’s funding – will still need to monitor all the children who were given these contaminated vaccines, for at least six months now, to see if polio manifests in them.

Besides this, India runs one of the world’s largest immunisation programmes. The entry of a dangerous or expensive vaccine into the immunisation basket can jeopardise thousands of lives.

Is the government being proactive and transparent in disclosure on the issue?

No. Despite repeated press requests for information on the controversy, the Union Health Ministry was silent on the matter. It did however issue a press release on Monday when Nadda inaugurated “Swacchta Mela” at AIIMS in Delhi. The ministry also called a special press briefing with only a few select news organizations (In the English press, Hindustan Times and the Times of India were invited) to discuss the polio controversy. They were told it would be an off-the-record meeting.

The lack of accountability of the union health ministry is not new – during the controversy over the Zika virus last year, there too as The Wire reported, the government hushed up the cases for months, escaping via technicalities in the International Health Regulations. On the other hand, shortly after this scandal, Tamil Nadu detected, tested, confirmed and reported to the public its one case of Zika, all within 11 days.

What kind of surveillance does the government take in general?

The government’s surveillance of the polio programme is carried out by the WHO with Indian government funding. If children are found to have “acute flaccid paralysis” (AFP), then those children are monitored with their stool samples to see if their paralysis is linked to polio or not.

It is this routine surveillance of children who were already showing AFP but are not yet confirmed for polio, whose stool sample showed the Type 2 polio virus.

The presence of the virus was further corroborated when the drug controller also seized vials of the vaccine. But in general, vaccines once approved are not regularly tested for quality or adulteration.

What measures is the government taking now now?

Firstly, the government says off record that it is stepping up surveillance. Stool samples, sewage samples and vaccine samples will be monitored more actively for the next few months.

The government is also stepping up immunisation – given that children have stopped getting the polio vaccine for Type 2 polio since 2016, children now exposed to Type 2 virus will not have the immunity for it. To avoid any new cases of polio, government sources have told The Wire that they will be administering trivalent injectable polio vaccine (IPV) in the areas suspected to be hit by this recent contamination and these vaccines will be trivalent, containing all 3 strains of the polio virus.

Lastly, the government has filed an FIR against the directors of Bio-Med. “The moment we found the contamination, we immediately stopped all production by this company,” said one government official.  “We could not prosecute in the case of Johnson and Johnson and their faulty hip implants but we can definitely prosecute here under the Drugs and Cosmetics Act, section 27(a). There is a ten years imprisonment possible here,” said another official.

Will this lead to any shortages of the vaccine in the country?

Not necessarily. Three government officials told The Wire that India’s massive immunisation programme, and for polio in particular, uses vaccines from a number of big companies, although Bio-Med was a significant supplier of the polio vaccine to the government. “There will be no disruption to either the bivalent or trivalent vaccine. There are another three or four companies who also supply the polio vaccine to India’s programme,” said an official.

What are some of the things the government’s investigation should look out for?

The strain of the Type 2 virus is not supposed to be in circulation and definitely not in the private market. A government official explained to The Wire that only the government’s National Institute of Virology in Pune is supposed to have a sample of this strain of virus preserved, after the government’s circular in 2016 that called for its destruction. So the government’s investigation will need to find out why Bio-Med managed to keep this virus.

The Wire also understands that Bio-Med doesn’t have a WHO pre-qualification certification. In India, this standard is not necessary for domestic sale but it is needed for export. Since the WHO asked countries to stop using the trivalent vaccine with Type 2 strain in it, there is little reason why Bio-Med should have been producing this vaccine at all, even if they claim it was for export. Either way, without a WHO pre-qualification, the company should not have been exporting anyway.

Third, the company had told the drug regulator in 2016 via undertakings, that they had recalled all stock from the market of their trivalent OPV as well as destroyed all their stock. The drug regulator needs to investigate whether the company lied. And they should also investigate where there was a lapse within the drug regulator itself that allowed companies to get away with undertakings. This could also reveal a larger number of other companies who have also not destroyed their stock.

Is this the first time such an incident has happened with the polio vaccine?

No. In 2016, cases of vaccine derived polio were detected in Hyderabad. Then too, the Central government and the WHO assured the public that this would not affect India’s polio free status. WHO called it a “low level threat.”

This article was updated on October 3.